Re: UMA panic under load

[Matthew Dillon]

    Here's another go at a patch (untested).

                                                -Matt

Index: kern/kern_exit.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_exit.c,v
retrieving revision 1.187
diff -u -r1.187 kern_exit.c
--- kern/kern_exit.c    10 Dec 2002 02:33:44 -0000      1.187
+++ kern/kern_exit.c    15 Dec 2002 01:36:35 -0000
@@ -289,6 +289,7 @@
         * may be mapped within that space also.
         */
        if (--vm->vm_refcnt == 0) {
+               ++vm->vm_exitingcnt;
                if (vm->vm_shm)
                        shmexit(p);
                vm_page_lock_queues();
@@ -297,7 +298,6 @@
                vm_page_unlock_queues();
                (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map),
                    vm_map_max(&vm->vm_map));
-               vm->vm_freer = p;
        }
 
        sx_xlock(&proctree_lock);
Index: vm/vm_map.c
===================================================================
RCS file: /home/ncvs/src/sys/vm/vm_map.c,v
retrieving revision 1.273
diff -u -r1.273 vm_map.c
--- vm/vm_map.c 1 Dec 2002 18:57:56 -0000       1.273
+++ vm/vm_map.c 15 Dec 2002 01:40:39 -0000
@@ -258,7 +258,7 @@
        vm->vm_map.pmap = vmspace_pmap(vm);             /* XXX */
        vm->vm_refcnt = 1;
        vm->vm_shm = NULL;
-       vm->vm_freer = NULL;
+       vm->vm_exitingcount = 0;
        return (vm);
 }
 
@@ -304,7 +304,7 @@
        if (vm->vm_refcnt == 0)
                panic("vmspace_free: attempt to free already freed vmspace");
 
-       if (--vm->vm_refcnt == 0)
+       if (--vm->vm_refcnt == 0 && vm->vm_exitingcount == 0)
                vmspace_dofree(vm);
 }
 
@@ -314,9 +314,10 @@
        struct vmspace *vm;
 
        GIANT_REQUIRED;
-       if (p == p->p_vmspace->vm_freer) {
-               vm = p->p_vmspace;
-               p->p_vmspace = NULL;
+       vm = p->p_vmspace;
+       p->p_vmspace = NULL;
+       if (--vm->vm_exitingcount == 0) {
+               KASSERT(vm->vm_refcnt == 0, ("vm_refcnt was not 0"));
                vmspace_dofree(vm);
        }
 }
Index: vm/vm_map.h
===================================================================
RCS file: /home/ncvs/src/sys/vm/vm_map.h,v
retrieving revision 1.92
diff -u -r1.92 vm_map.h
--- vm/vm_map.h 22 Sep 2002 04:33:43 -0000      1.92
+++ vm/vm_map.h 15 Dec 2002 01:38:29 -0000
@@ -219,7 +219,7 @@
        caddr_t vm_daddr;       /* (c) user virtual address of data */
        caddr_t vm_maxsaddr;    /* user VA at max stack growth */
 #define        vm_endcopy vm_freer
-       struct proc *vm_freer;  /* vm freed on whose behalf */
+       int     vm_exitingcnt;  /* several processes zombied in exit1  */
 };
 
 #ifdef _KERNEL

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